Means for cooling electric apparatus



July 5, 1932. F. G. BAUM 1,865,499. I

MEANS FOR COOLING ELECTRIC APPARATUS Filed Sept. 15. 1929 INVENTOR doe:0079M ATTORNEY Patented July 5, 1932 UNITED STATES FRANK G. BA'UM, FCASSEL, CALIFORNIA MEANS FOR COOLINGELEGTRIC APPARATUS Application filedSeptember 13, 1929. Serial No. 392,421.

In electric: apparatus there are various unavoidable losses such as corelosses and electrical resistance losses. The energy ex: pended by suchlosses within the apparatus appears in the form of heat energy. The rateit is a purpose of my invention to provide a.

means for removingthe heat developed in such apparatus.

In general, stationary electrical apparatus such as transformerscomprise a tank in '15 which the induction coilsare submerged ininsulating oil. During the operation of the apparatus, the heatdeveloped by the core and the coils is transferred to the oil in contacttherewith. The oil thus heated rises to the top of the tank, movestoward thewalls of the tank to which the heat absorbed from the coils istransferred, and descends to the bottom of the tank to again come incontact with the coils, taking theplace of oil which 95 was heated andmoved upwardly. Thus, a

continuous circulation of the oil takes place within the casingtransferring the heat developed in the winding to the walls of thetank'from which it is transferred to the surrounding medium. In somecases conduits have been provided which extend from the top of the tankto the bottom thereof and through which the oil circulates. The conduitspresent a larger surface tothe atmosphere which circulates between theconduits and the tank. In other instances, the oil in the tank is watercooled, the oil being continuously circulated through coils which arecooled by water to which the heat is transferred. This method of coolingrequires expensive auxiliary apparatus and an abundant supply of water.

By my invention, I cool electrically apparatus by expending the heatenergy developed therein in theevaporation of moisture. I employ aconstruction in which air charged with entrained moisture is circulatedin contact with the outer surface of the walls of the casing enclosingthe electrical apparatus.

Specifically, I provide a housing which surrounds the tank or casing ofthe stationary electric apparatus. The housing is so located withrespect to the walls of the tank that a passage is provided around thetank for a circulating medium. Inlet and outlet openings are provided inthe walls of the housing and are so located that air flowing from one tothe other is caused to circulate around the tank of the inductionapparatus. A fan is mounted within the housing to cause air to flowtherethrough by way of said openings. Adjacent the inlet to the housing,I provide a spray forming device for introducing moisturein the form offinely divided'particles into the air entering the housing. Foraminouspartition walls transverse to the direction of movement of the airarelocated with in the housing behind the spray forming device relative tothe direction of movement of the air through the housing. Theseforaminous partition walls through which the air is caused to flow, aremaintained in a moist condition, thereby providing a large wetted areafrom which moisture may be evaporated.

I shall now describe one embodiment of my invention in connection withthe accompanying drawing in which Fig. 1 is a side elevation of astationary induction apparatus with the outer housing in section, theouter electric bushings etc. not being shown;

Fig. 2 is a transverse section of the same taken on the line 22 ofFigure 1.

The embodiment of this invention as illustrated comprises a stationaryinduction apparatus 1, such for example as an ordinary transformer,which consists of a tank or casing in which the core and the coils woundthereon are submerged in oil. Surrounding the tank is a housing 2.

The housing 2 is spaced from the transformer tank 1 to provide a passagebetween the housing and the outer wall of the tank. The housing may beconstructed of sheet metal formed to the desired shape, in this instancecylindrical. By constructing the housing in two parts, as shown, it maybe readily assembled about the transformer, the edges of the parts beingbent outwardly to form flanges 3 forsecuring the parts together by meansof bolts or the like. In both halves of the housing at the center of thesurface thereof, openings 4 and 5 are provided which in the assembledstructure constitute opposed inlet and outlet openings respectively. Themetal around the openings 4 and 5- is flared outwardly forming circularflanges 6 which with the screens 7 covering the openings from abell-shape housing for fan motors 8, mounted at each opening; In certaincases only one motor fan may be used as desired. In such constructionthe singlemctor is preferably mounted at the inlet opening in thehousing.

The motors 8 are centrally mounted in the bell-shape housings formed onthe sides of the housing 2, and are supported therein by circular screensupports 9 and 10 which are secured at the outer edge to the housing andat the inner edge to the bearings of the me or. On the extended end ofthe motor shafts adjacent the screen covered openings in, the housing 2,fans 11 are secured which, when the motors are operating, force airthrough the housing by way of the inlet 4 and outlet 5.

At the inlet opening 4, a spray forming device 12 is directed toward thefan 11. The sprayer has a conduit 13 connected thereto which extendsthrough the screen 7 to a source of fluid supply (not shown). Thesprayer 12 introduces moisture into the incoming air in the form offinely divided par ticles which is partly evaporated by the and partlycarried as entrained moisture in the air. A suitable valve 14 may beprovided between the supply conduit 13 and the sprayer 12 for regulatingthe quantity of moisture introduced into the air.

Within the housing, radial screens 15- eX- tending between the housingand the transformer tank, are providec. The first set of screens areangularly displaced through an angle of approximately 45 on oppositesides of the longitudinal plane containing the centers of the inlet andoutlet openings, the second set of screens being displaced through. anangle of 90 on opposite sides of the same plane. Upon the screens 15entrained moi. ture carried by the air flowing through the casing isdeposited and maintains the screens in a moist condition. The excessmoisture deposited on the screens 15 is drained from the housing throughthe drain 16 provided therefor.

The operation of the device above described is as follows: The heatdeveloped in the coils and core of the transformer during the operationthereof is transferred by the circulation of the oil therein to thewalls of the tank. The fan motors 8 are operated, the fans 11 causingair to flow through the housing 2 by way of the openings 4 and 5. At theopening 4, moisture is introduced into the air entering the housing 2 bythe spray forming device 12. Part of the moisture introduced into theair at the inlet 4 is evaporated by the air, the evaporation beingcaused by the expenditure of heat energy in the air, thereby cooling theair. A portion of the moisture not evaporated by the heat of the air iscarried entrained in the air and is evaporated by heat taken from thewall of the transformer tank. The remainder of the moisture carried bythe air is deposited upon the screens 15 within the casin g andmaintains the screens in a wet condition forming efficient evaporationareas. Thus, heat is absorbed from the tank by evaporation of moisturecarried by the air and is transferred to the air which is cooled by theevaporation of moisture at the inlet and at the wet screens 15. The airafter absorbing the heat of this tank is then eX- hausted through theopening 5. Excess moisture deposited in the casing is drained therefromby a suitable drain 16.

In cooling by evaporation as is done in the construction shown in thedrawing and above particularly described, the quantity of water requiredto cool the mechanism is much less than that required in constructionsin which the mechanism is cooled by'the transfer of heat to the coolingwater. The reason a much less quantity of water is required in coolingby evaporation is the fact that 970 B. t. u. are required to evaporateone pound of water, whereas when the heat is'transferred to the coolingwater to raise the temperature thereof, only one B. t. u. is absorbed bya pound of water for each degree rise in temperature.

It will be readily apparent to those skilled in the art that I havedevised a cooling device for electrical apparatus that is efficient inoperation, requires only a relatively small fluid supply and is simplein construction.

It is obvious that various changes may be made in the illustratedembodiment above particularly described within the principle and scopeof my invention as expressed in the appended claims. 7

I claim:

1. Means for cooling a tank containing electrical apparatus comprising,a housing surrounding and enclosing the tank and spaced therefrom toprovide a passage between the tank and the housing, said housing havinginlet and outlet openings therein, means for causing air to flow throughthe inlet in the housing and around the tank to the outlet in thehousing, and means adjacent the inlet in the housing and in advance ofthe air moving means relative to the direction of movement of the airfor introducing moisture into the air flowing therethrough.

2. A cooling device for a tank containing electrical apparatuscomprising, a housing surrounding and enclosing said tank and spacedtherefrom to provide a passage between the tank and the housing, thehousing having inlet and outlet openings therein,

. screens in a wet condition.

3. A cooling device for a tank containing electrical apparatuscomprising, a housing surrounding and enclosing the tank and spacedtherefrom to provide a space between the housing and the tank, saidhousing having inlet and outlet openings therein, means for causing airto flow through the inlet in the housing and around the tank to theoutlet in the housing, transverse screens in said housing, and meansadjacent the inlet in the housing for introducing moisture into the airflowing through the housing.

4. A cooling device for a tank containing electrical apparatuscomprising, a housing surrounding and enclosing said tank and spacedtherefrom, said housing having inlet and outlet openings therein, a fanwithin said housing for causing air to flow throughthe inlet in thehousing and around the tank to the outlet in the housing, transversescreens in said housing, and a spray forming device adjacent said inletfor introducing moisture into the air flowing therethrough.

5; A cooling device for a tank containing electrical apparatuscomprising, a housing surrounding and enclosing the tank and spacedtherefrom, said housing having inlet and outlet openings therein, a fanwithin said housing adjacent the inlet opening therein, means fordriving said fan to cause a current of air to flow through the inlet inthe housing and around the tank to the outlet in the housing, and meansadjacent the inlet in the housing for introducing moisture into the airflowing therethrough.

6. A cooling device for a tank containing electrical apparatuscomprising, a housing surrounding and enclosing the tank and spacedtherefrom, said housing having inlet and outlet openings therein, fanswithin said housing adjacent the inlet and outlet openings therein,means for driving said fans to cause a current of air to flow throughthe inlet in the housing and around the tank to the outlet in thehousing, and means adjacent the inlet in the housing for introducingmoisture into the air fiow'ng therethrough.

7 A cooling device for a tank containing induction coils comprising, acylindrical housing surrounding and enclosing the tank and spacedtherefrom, said housing having opposed inlet and outlet openingstherein, bell-shape motor housings extending from said housing at theopenings therein, motors mounted within said bell-shape housings, fansmounted on said motors for causing air to flow through the inlet in thehousing around the tank to the outlet, and means adjacent the inlet forintroducing moisture into the air flowing through the inlet.

8. A cooling device for a tank containing induction coilscomprising,acylindricalhousing surrounding and enclosing the tank andspaced therefrom, said housing havlng op posed inlet and outlet openingstherein, bellshape motor housings extending from said housings at theopenings therein, motors mounted within said bell-shape housings, fansmounted on said motors for causing air to flow through the inlet in thecylindrical housing and around the tank to the outlet in the housing,screens within the cylindrical housing transverse to the direction ofmovement of the air therein, and a spray forming device adjacent theinlet for introducing moisture into the air flowing therethrough.

9. Means for cooling encased electrical ap paratus comprising a housingenclosing the casing and spaced therefrom to form a passage between thecasing and the housing, the housing having inlet and outlet openingstherein, means for causing air to flow through the inlet in the housingand around the casing to the outlet in the housing, and means at theinlet to said housing, in advance of the means for causing air to flowthrough the housing relative to the direction of motion of air throughthe housing, for introducing moisture into the air flowing through thehousing.

10. Means for cooling encased electric apparatus comprising a housingenclosing the casing about the electric apparatus and spaced therefromto form a passage between the casing and the housing, the housing havinginlet and outlet openings therein, means for causing air to flow throughthe inlet in the housing and around the casing to the outlet in thehousing, foraminous partitions within the housing transverse to the flowof air therethrough, and means for maintaining the foraminous partitionsin a wet condition.

In witness whereof, I hereunto subscribe my signature.

FRANK G. BAUM.

